2. On a cutting board with a rolling pin, gently press down on the cardamom pods to separate the seeds from the husks; discard the husks. Add the cloves and cumin seeds to the cardamom seeds. With the pin, crush them together to break them up.

3. In a blender, combine the yogurt, crushed seeds, garlic, ginger, jalapeno, cinnamon, and a generous pinch of salt and pepper. Work the mixture to a coarse puree. Add the mint and cilantro leaves. Work again to make a puree.

4. Remove any giblets from the hens. Wipe them out. Spoon about 1 tablespoon of the yogurt mixture into each hen. Set them in the roasting pan and tie the legs together with kitchen twine.

5. Spread the remaining yogurt mixture on the skin of the hens. Refrigerate for at least 30 minutes or for up to 4 hours.

6. Set the oven at 425 degrees. Let the hens sit at room temperature for 20 minutes.

7. Roast the hens for 50 to 60 minutes, or until a thermometer inserted into the thickest part of the thigh registers 170 degrees. Remove from the oven. Set aside 2 hens for the biryani. Divide the watercress among 4 dinner plates. Set a hen in the middle of each one.